Keeping Nylon Conditioned? 3

[DragonForge]

Hello Chaps

Great forum you have here.

We are currently injection moulding training swords for the martial arts industry. At present we are using an impact modified barium filled pp and it certainly does the job.

However, the market is demanding a stiffer product so we have been experimenting with different materials (adding glass to the pp did not work).

We have found that Nylon 6 if conditioned by immersing in water for a week has the exact properties that we are looking for. However, as the nylon starts to equalise with the atmosphere it becomes too brittle.

Does anybody know of a way to make the nylon retain the water - would lacquering or applying a coat of wax work for instance?

Any help or suggestions would be appreiated.

Thanks

 

[Pud]

DragonForge:

Try these: Polymer Powders Technology, Hartlepool.

We are about to use their iron powder filled nylon with s.g. of 4.9, but they will make up whatever you want. Small qty's too.

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[DragonForge]

Brillaint Harry!

Thanks for the info - I'll contact them today.

 

[Demon3]

I'd not be surprised if ethylene glycol (glycerol) is a decent plasticizer for your nylon. It's polar, safe and not so volatile.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[btrueblood]

Interesting thought Chris. Caution to users of that idea, though - glycols are very hygroscopic, and part of its action as a plasticizer for nylon may be due to hygroscopicity (say that word 3 times fast). I'm working on a project using a glycol for hydraulic fluid, and have to include a means to recalibrate reservoir levels as ambient humidity changes, the reservoir slowly gives up or takes in water until the glycol equilibrates to the atmosphere.

 

[Compositepro]

I'm surprised that any thermoplastic will work adequately in an application that requires a high degree of flex but must always come back to its original shape. That requires a high yield strength and no creep which not the strong points of thermoplastics. Glass and carbon fibers are are ideal for achieving this effect. A couple of strips of glass fiber ribbon impregnated with PP or nylon could be inserted in your mold.

 

[Demon3]

If it takes up water (which it will as you said) then great. That's what we want, something that sucks in some water to help plasticize.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[patprimmer]

Ethylene glycol/water mix is used as engine coolant in virtually all cars for many years now, along with GF nylon6.6 radiator header tanks. The tanks do not become plasticised beyond what you would expect from constant contact with water on one side, especially considering that water is often at around 100 deg C

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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for site rules

 

[Pud]

OK, the OP is a moulder based in the UK.

I would guess he has not got a compounding facility on-site.
So how does one incorporate ethylene glycol in his process?
Mix it in a tumbler? Great until it goes in the hopper and then the glycol drains off and runs down the hopper into the machine throat! Hardly commensurate with consistency.

Way back in the stone age, toughened nylons used to be called "pre conditioned" as they did not require conditioning (although they were obviously better when done so).

Toughened nylon (eg Zytel ST801/ EMS AZ3, to name two of squillions) will be fine. If heavier is required, which the op indicates not), then some sort of additive can be COMPOUNDED in - not added at the machine!

Last word...

H

http://www.tynevalleyplastics.co.uk